Gastroesophageal varices develop when normal blood flow to the liver is obstructed by scar tissue caused by cirrhosis. The scar tissue forces blood into smaller vessels surrounding the esophagus or stomach, causing the vessels to swell, leak and eventually rupture. Approximately 80 percent of patients with cirrhosis develop varices of the esophagus, and approximately 17 percent develop gastric varices (Hepatology, 16, 1343-49 (1992)). Bleeding occurs in approximately 36 percent of patients and is associated with a mortality rate of at least 20 percent, which increases to 50 percent with each bleeding episode. In the United States alone, gastroesophageal varices due to cirrhosis account for more than 25,000 deaths and 373,000 hospitalizations annually (J. Clin. Gastroenterol., (2014); U.S. Center for Disease Control and Prevention, (2014)).
The primary prophylactic treatment for variceal bleeds is non-selective beta-blockers that reduce portal hypertension. Studies have shown that beta-blockers are only effective in 38 percent of patients (Aliment. Pharmacol. Ther., 30, 48-60 (2009)). Application of cyanoacrylate glue (Covidien, TissueSeal and Ethicon) into gastroesophageal varices has been shown to eliminate bleeds, however, the glue has a limited working time after mixing and poses a risk of systemic embolization.
Endoscope band ligation may be used to treat acute bleeds or when non-selective beta-blockers have failed. Unfortunately, band ligation can have a number of drawbacks, including high cost, low efficacy and various safety concerns. Significant training is required to deliver the bands in a controlled manner. Furthermore, the bulge that forms when a varix is banded may obscure the field of view, which may limit the ability to maneuver the endoscope and may make subsequent band placements more difficult. As the number of deployed bands increases, the likelihood of the endoscope accidentally dislodging a band and causing a bleed increases. These factors may limit the number of bands that can be deployed to approximately 6 per session. On average, 2-4 procedures may be required to eradicate all of the varices. These treatments may be expensive and may increase the risk of acute bleeds occurring from varices that are awaiting treatment. These untreated bleeds may be associated with a four-fold increase in hospital costs, including possibly increased hospitalization times (Value Heal., 11, 1-3 (2008)). Ulcers and strictures also may tend to form in the mucosal lining of the esophagus when the bands slough off. Some studies have shown that more than 12 percent of patients experience re-bleeding after a band ligation procedure (BMC Gastroeneterol., 10, 1-10 (2010)). The average band ligation procedure may take more than 50 days to complete, with varices possibly recurring in up to 75 percent of patients after two years. Some studies claim that these re-bleeds are estimated to result in a four-fold increase in both the duration of hospitalization and treatment costs (Value Heal., 11, 1-3 (2008)).
The risks and costs that may be associated with existing endoscope banding treatments may be too high to warrant earlier intervention to prevent recurrence of varices and bleeds (Hepatology 21, 1517-1522 (1955); ACTA Medica. Litu., 19, 59-66 (2012). There is an ongoing need for an easier-to-use and more cost-effective system capable of coagulating multiple varices in a single procedure without damaging surrounding mucosal tissues.